Notice of RetractionCultivation of aerobic granular sludge in sequencing batch reactor with short cycle

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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In a sequencing batch reactor (SBR) with 2.5h operation cycle, aerobic granular sludge (AGS) was developed successfully. The main diameter and sludge volume index (SVI) of AGS cultivated were 1~3 mm and 33 ml g^-1. There were significant effects of pH value on aerobic granulation. The dosage of 300 mgNaHCO₃ l^-1 to influent could avoid the overgrowth of filamentous bacteria in bioreactor. Aerobic granulation improved largely the metabolic activities of microorganisms in sludge. The oxygen uptake rate (OUR) of AGS reached 55 mgO₂ l^-1 h^-1. The AGS developed can quickly remove most of nutrients in sewage. For low strength sewage, the removal efficiencies of COD, NH4⁺-N and TP were 91.1%, 99.0%, and 98.8%, respectively; while for strong sewage, the SBR with AGS cultivated was an excellent pretreatment process.